Data Management Plan (Deprecated)

Original Product: Hydroflattened Digital Elevation Model (DEM) data covering the Washington DNR 3DEP Processing project area.

Geographic Extent of Original Data: This dataset and derived products encompass an area covering approximately 562,137 acres of Eastern Washington.

Original Dataset Description: The Washington DNR 3DEP Processing Lidar project called for the planning, acquisition, and processing of lidar data collected to Quality Level 1 (QL1) standards. Project specifications are based on the U.S. Geological Survey National Geospatial Program LIDAR Base Specification, Version 2.1. The data was developed based on the NAD83 2011 horizontal datum and the NAVD88 Geoid 18 vertical datum. Data was projected in Washington State Plane North, U.S. feet. Lidar data was delivered as calibrated and classified LAS 1.4 files. Lidar flight line swaths were processed to create 1,097 classified LAS 1.4 files delineated in 5,000ft x 5,000ft tiles. Each LAS file contains lidar point information, which has been calibrated, controlled, and classified. Class 2 (ground) lidar points in conjunction with the hydro breaklines were used to create 1,097 2.0 foot hydro-flattened Raster DEMs delineated in 5,000ft x 5,000ft tiles. Non-Vegetated Vertical Accuracy (NVA) was assessed using 64 check points located on bare earth in clear, unobstructed areas. Vegetated Vertical Accuracy (VVA) was assessed using 43 check points in Tall Grass, Forest, and Shrub landcover types. Additional products include classified LAS files, intensity images, highest hit surface models, and 3D breaklines of rivers and lakes within the study area.

Ground Condition of Original Data: Ground condition was free of snow and acquisition occurred free of smoke, fog and cloud cover.

This metadata record supports the data entry in the NOAA Digital Coast Data Access Viewer (DAV). For this data set, the DAV is leveraging the USGS GeoTiff files hosted by USGS on Amazon Web Services.

Lineage Statement:
The NOAA Office for Coastal Management (OCM) ingested references to the USGS GeoTiff files that are hosted on Amazon Web Services (AWS), into the Digital Coast Data Access Viewer (DAV). The DAV accesses the raster data as it resides on AWS under the usgs-lidar-public-container.

Process Steps:

• 2021-01-29 00:00:00 - Lidar Pre-Processing: 1. Review flight lines and data to ensure complete coverage of the study area and positional accuracy of the laser points. 2. Resolve kinematic corrections for aircraft position data using kinematic aircraft GPS and static ground GPS data. 3. Develop a smoothed best estimate of trajectory (SBET) file that blends post-processed aircraft position with sensor head position and attitude recorded throughout the survey. 4. Calculate laser point position by associating SBET position to each laser point return time, scan angle, intensity, etc. Create raw laser point cloud data for the entire survey in *.las format. Convert data to orthometric elevations by applying a Geoid 18 correction. 5. Import raw laser points into manageable blocks to perform manual relative accuracy calibration and filter erroneous points. Classify ground points for individual flight lines. 6. Using ground classified points per each flight line, test the relative accuracy. Perform automated line-to-line calibrations for system attitude parameters (pitch, roll, heading), mirror flex (scale) and GPS/IMU drift. Calculate calibrations on ground classified points from paired flight lines and apply results to all points in a flight line. Use every flight line for relative accuracy calibration. 7. Adjust the point cloud by comparing ground classified points to supplemental ground control points.
• 2021-01-29 00:00:00 - Lidar Post-Processing: 1. Classify data to ground and other client designated classifications using proprietary classification algorithms. 2. Manually QC data classification 3. After completion of classification and final QC approval, calculate final NVA, VVA, and density information for the project using ground control quality check points.
• 2021-01-29 00:00:00 - Hydro-flattening Breaklines and Hydro-flattened DEM creation: Water boundary polygons were developed using an algorithm which weights lidar-derived slopes, intensities, and return densities to detect the water's edge. The water's edge was then manually reviewed and edited as necessary. Elevations were assigned to the water's edge through neighborhood statistics identifying the lowest lidar return from the water surface. Lakes were assigned a consistent elevation for an entire polygon while rivers were assigned consistent elevations on opposing banks and smoothed to ensure downstream flow through the entire river channel. These breaklines were incorporated into the hydro-flattened DEM by enforcing triangle edges (adjacent to the breakline) to the elevation values derived from the breakline. This implementation corrected interpolation along the hard edge. Breaklines were also used to classify all ground points within the identified water bodies to class 9 (water).
• 2024-10-16 00:00:00 - The NOAA Office for Coastal Management (OCM) created references to the USGS GeoTiff files that were ingested into the NOAA Digital Coast Data Access Viewer (DAV). No changes were made to the data. The DAV will access the raster data as it resides on Amazon Web Services (AWS) under the usgs-lidar-public container. This is the location of the GeoTiffs that are being accessed: https://prd-tnm.s3.amazonaws.com/index.html?prefix=StagedProducts/Elevation/OPR/Projects/WA_DNR_3DEP_Processing_2019_D20/WA_DNR_3DEP_Processing_1_2019/TIFF/

Data is available online for bulk and custom downloads.

Data is backed up to cloud storage.